There are Equipment Commendation Vendor on each planet. You can use the commendations to buy gear. I know I bought a decent vest from the Ord Mantel Commendation Vendor.

From what I read in the TOR forums (so I don’t know the accuracy of the information) you have to use the commendations on that planet, there are no refunds (you can sell the item back, but you get credits not commendations) and many of the items have lightside/darkside requirements.